Field of the Invention
The present invention relates to a damper, and more particularly, a dual mode tuning type dynamic damper including a lateral mode capable of tuning a resonant frequency at a bending mode and a drive shaft device and a vehicle thereby.
Description of Related Art
Generally, vehicle driving generates resonance with rotation degree component of a power train and vehicle wheels (wheel and tire) by that the power of a power train is transmitted to vehicle wheels through a drive shaft.
For example, the rotation secondary degree of the power train and the rotation degree component (1.9-2.1 degree) adjacent thereto generate the resonance, and the resonance is progressed to vibration through the drive shaft along with beat noise (driving booming noise) sounding like “ung-ung-ung.”
Therefore, various means have been applied in order to improve the beat noise and the vibration.
For example, there is a resonance frequency avoidance method.
The resonance frequency avoidance method is a method of separating the vibration mode of the drive shaft from the vibration mode of the power train by coupling a damper to the drive shaft, observing that the driving booming noise and vibration are generated by resonance when the vibration mode of the power train and the vibration mode (bending mode) of the drive shaft are coincided with each other.
As a result, the damper (generally, a dynamic damper) greatly improves a frequency avoidance performance of a problem so that the driving booming noise and vibration minimally occur.
As another example, there is a resonance rotation degree avoidance method.
The resonance rotation degree avoidance method is a method avoiding resonance of the drive shaft by greatly altering ball type joint specifications applied to the drive shaft and the vehicle wheels.
As a result, an eight balls type joint greatly improves rotation degree avoidance performance of a problem in comparison with a six balls type joint to minimize the driving booming noise and vibration generation.
However, the resonance rotation degree avoidance method should upgrade ball joint specifications to result in greater manufacturing cost rise.
Otherwise, the resonance frequency avoidance method has a merit of relatively low manufacturing cost by ½ in comparison with the resonance rotation degree avoidance method, but it is impossible to tune a lateral mode of the damper so that the number of the damper should be increased in order to improve the resonance frequency avoidance performance. The increased number of the damper causes greater manufacturing cost increase by increased raw material cost so that it is bound to be a limitation on the application.
This is caused because the damper is not tunable lateral mode tuning structure having the greatest influence by taking a bending mode as a main mode, whereas the beat noise (driving booming noise) and vibration caused by the drive shaft is in a range of 140˜160 Hz appearing in the horizontal direction (lateral direction) of the drive shaft.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.